Storing custom code, E.G - javascript

A client of mine uses javascript banners, and would like to be able to add them manually in the CMS, however SilverStripe always strips out all the " & 's. So it never works. have tried lots all the different data types, but it always escapes the special characters.

is there any way at all to do this?
If the codes followed a similar pattern I would create a template and let the client just add in the URL that changes etc, but the code is always different depending on the banner supplier. here's an example: